1. Field of the Invention
The present invention relates generally to a fuel injection apparatus, and more particularly to a fuel injection apparatus for an internal combustion engine.
2. Description of the Related Art
A fuel injection apparatus is often used in, for example, an internal combustion engine for controlling the power generated by the internal combustion engine. A conventional fuel injection apparatus is, for example, disclosed in Japanese patent laid-open publication 62(1987)-93481 The conventional type fuel injection apparatus is shown in FIG. 2.
Referring now to the FIG. 2, the fuel injection apparatus 50 basically includes a main body 51, a solenoid valve 52, a valve shaft 53 and a valve holder 54. A fuel chamber 55 is defined in the main body 51. An air conduit 56 is formed in the main body 51 for introducing pressurized air to the fuel chamber 55. A fuel inlet port 57 is arranged in the main body 51. Fuel conduits 58a and 58b are connected with the main body 51. A fuel tank 59 is connected with the fuel conduit 58a, and a fuel pump 60 is arranged between the fuel inlet port 57 and the fuel tank 59. A fuel injector 61 is arranged on a surface of the main body 51. A fuel supplying rate to the fuel chamber 55 is controlled by the fuel injector 61.
The solenoid 52 is arranged on an upper portion of the main body 51, and the solenoid 52 is covered with an outer cover 52a. The axial movement of valve shaft 53 is controlled in accordance with an operating condition of the solenoid 52. The cylindrical shaped valve holder 54 is connected with the main body 51, and the valve shaft 53 penetrates through the main body 51 and the valve holder 54. Fuel and pressurized air are mixed uniformly in the fuel chamber 55.
In operation, an electrical signal is applied to the solenoid 52. This energizes the solenoid 52 and moves the valve shaft 53 to the open position. When the electrical signal is not applied to the solenoid 52, the valve shaft 53 does not move and the valve shaft 53 remains at the closed position as shown in FIG. 2. The air-fuel ratio is controlled in accordance with the operation of the fuel injector 61.
There are problems in the above-described design or arrangement. In operation, a high speed pumping operation and/or a high compression mixing operation are required for generating a desired air-fuel mixture. Particularly in a 2-cycle type internal combustion engine, a high pressure air-fuel mixture is required for injection in the engine during a compression phase thereof. However, the described known art cannot establish a high speed and/or high compression mixing operation.